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Screen Capture Module via wxPerl

by jmlynesjr (Hermit)
on Oct 23, 2012 at 17:56 UTC ( #1000505=CUFP: print w/replies, xml ) Need Help??

The Screen Capture wxPerl script is now in modular form. My first try at creating a (very simple) module and using POD.


Update-added to POD sections

Module wxScreenCapture
use strict; use warnings; package WxScreenCapture; use parent qw(Exporter); our @EXPORT = qw(take_screenshot file_entry_dialog_simple file_entry_d +ialog_standard); use Wx qw(:everything); use Wx::Event qw( EVT_PAINT ); =head2 # # Copy the screen to the output file-similar to wxBook pg 139 example. # =cut sub take_screenshot { my($self, $file ) = @_; $self->Refresh; # without Refresh and Updat +e $self->Update; # the underlying window is c +aptured my $screen = Wx::ScreenDC->new(); my( $x, $y) = $screen->GetSizeWH(); my $bitmap = Wx::Bitmap->new($x,$y,-1); my $memory = Wx::MemoryDC->new(); $memory->SelectObject( $bitmap ); $memory->Blit(0,0,$x,$y, $screen, 0, 0); # copy the scr +een to the bitmap $bitmap->SaveFile( $file , wxBITMAP_TYPE_BMP ) ; # copy the + bitmap to the output file } =head2 # # Ask for the output filename - simple text entry dialog # =cut sub file_entry_dialog_simple { my( $self ) = @_; my $textvalue = "capture.bmp"; my $dialog = Wx::TextEntryDialog->new ( $self, "Enter the Screen Capture output filename\n(Cancel will u +se the default filename shown below)\n", "Screen Capture Output File Entry", $textvalue, wxOK | wxCANCEL ); if( $dialog->ShowModal == wxID_OK ) { $textvalue = $dialog->GetValue; } $dialog->Destroy; return $textvalue; } =head2 # # Ask for the output filename - standard file dialog # =cut sub file_entry_dialog_standard { my ( $self ) = @_; my $caption = "Choose a Screen Capture Output Filename"; my $wildcard = "*.bmp"; my $defaultDir = "."; my $defaultFilename = "capture.bmp"; my $filevalue = $defaultFilename; my $fileDialog = Wx::FileDialog->new($self, $caption, $defaultDir, + $defaultFilename, $wildcard, wxFD_SAVE | wxFD_OVERWRITE_P +ROMPT); if ($fileDialog->ShowModal() == wxID_OK ) { $filevalue = $fileDialog->GetPath(); } $fileDialog->Destroy; return $filevalue; } 1; __END__ =head1 NAME =head1 SYNOPSIS Module to capture a screen to a file. Written in wxPerl. =head1 DESCRIPTION This module exports three subroutines: take_screenshot, file_entry_dia +log_simple, and file_entry_dialog_standard. take_screenshot uses Wx:: +ScreenDC and Wx::MemoryDC device contexts and a Wx::Bitmap. Blit copi +es the ScreenDC to the MemoryDC Bitmap which is then copied to an out +put file. file_entry_dialog_simple provides a text_entry_dialog for r +equesting the capture filename. file_entry_dialog_standard provides t +he full directory/file entry screen for requesting the capture pathna +me. If the frame you wish to capture is smaller than the full screen, the +background windows will also be captured. =head1 USAGE use Wx qw(:everything); use Wx::Event qw( EVT_PAINT ); use WxScreenCapture; my $app = Wx::SimpleApp->new; my $frame = Wx::Frame->new(undef, -1, "Screen Capture Module Example", + [0,0], [1024,768] , wxDEFAULT_FRAME_STYLE); EVT_PAINT( $frame, \&onPaint); my $file = file_entry_dialog_standard($frame); $frame->Show; take_screenshot($frame, $file); $app->MainLoop; sub onPaint{} #paint the screen to be captured here. =head1 AUTHOR James M. Lynes, Jr. <> Lakeland, Florida USA October 21,2012. Original author: "PodMaster" from Perl Monks-2003 (no idea of real ide +ntity-not active for 6+ years) =head1 BUGS/FEATURES To capture the complete sample graphic(not included in this module def +inition), the frame size had to be set to the screen size of [1024x768]. Using wxDefaultSize ca +used the screen to paint in two passes and the capture to clip. If the frame is not defined large enough, par +ts of underlying windows will also be captured. =head1 SEE ALSO "The wxBook" - Cross-Platform GUI Programming with wxWidgets - Smart, Hock, and Csomor The wxWidgets documentation L<> The Citrus Perl Distribution L<> =head1 LICENSE This program is free software; you can redistribute it and/or modify i +t under the same terms as Perl itself. =cut
Test Script
use strict; use warnings; use Wx qw(:everything); use Wx::Event qw( EVT_PAINT ); use WxScreenCapture; =head2 # # Main Application # =cut my $app = Wx::SimpleApp->new; my $frame = Wx::Frame->new(undef, -1, "Screen Capture Module Example", + [0,0], [1024,768] , wxDEFAULT_FRAME_STYLE); EVT_PAINT( $frame, \&onPaint); my $file = file_entry_dialog_standard($frame); $frame->Show; take_screenshot($frame, $file); $app->MainLoop; =head2 # # Generate a sample graphic screen to capture # =cut sub onPaint{ my($self,$event)=@_; my $screen = Wx::PaintDC->new($self); $screen->SetBackgroundMode( wxTRANSPARENT ); $screen->SetFont(Wx::Font->new( 12, wxFONTFAMILY_ROMAN, wxNORMAL, +wxBOLD)); for(0..17){ my $c = $_ * 15; $screen->SetTextForeground( Wx::Colour->newRGB(0,0,$c) +); $screen->DrawRotatedText("wxPerl",100 ,100 ,$c); } $screen->DrawRotatedText("wxPerl and PodMaster",000 ,4 +00 ,0); $screen->DrawRotatedText("are messing up your screen", +000 ,450 ,0); for(0..17){ my $c = $_ * 15; $screen->SetTextForeground( Wx::Colour->newRGB(0,$c,0) +); $screen->DrawRotatedText("wxPerl",200 ,200 ,$c); } $screen->DrawRotatedText("wxPerl and PodMaster",100 ,5 +00 ,0); $screen->DrawRotatedText("are messing up your screen", +100 ,550 ,0); for(0..17){ my $c = $_ * 15; $screen->SetTextForeground( Wx::Colour->newRGB($c,0,0) +); $screen->DrawRotatedText("wxPerl",300 ,300 ,$c); } $screen->DrawRotatedText("wxPerl and PodMaster",200 ,6 +00 ,0); $screen->DrawRotatedText("are messing up your screen", +200 ,650 ,0); }

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Re: Screen Capture Module via wxPerl
by zentara (Archbishop) on Oct 23, 2012 at 18:37 UTC
    It dosn't seem to capture a Screenshot for me, on Linux. The script runs, asks for a filename, and even writes a little demo screen; but the capture.bmp produced is just a thin colored bar.... not the Screen.

    I'm not really a human, but I play one on earth.
    Old Perl Programmer Haiku ................... flash japh

      zentara, I don't know what to say. It runs correctly for me. Will have to wait and see if others report similar problems and go from there.

      I am running Ubuntu 10.10, Citrus Perl 16.1, wxWidgets 2,8.x, and Wx 0.9914.


Re: Screen Capture Module via wxPerl
by Anonymous Monk on Oct 24, 2012 at 06:39 UTC

      Great. Thanks. Will do. Proper usage follows learning the basic syntax.:)

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[ambrus]: If you don't do that, some people will be able to use only two thirds of the available screen area, or have to prepare three versions of their slides, each of which is a waste that you could avoid with one simple phrase in the call for papers.
[Corion]: As for somebody hosting national conferences, we don't always know the kind of connectors and aspect ratios available ;)
[ambrus]: Corion: well sure, but that's the similar to any printed document, and the margin is diminishing with today's technology. Video games no longer have to assume that the CRTs won't show the edges of the screen.
[Corion]: If you cram your slides with that much information, they might work in an "offline" situation but not very well for a live presentation IMO
[ambrus]: Corion: in that case I also ask the people who rent the conference rooms to tell conference organizers about the available tech.
[Corion]: ambrus: No, you're misunderstanding. If you place content too far on the left/right/top/ bottom, people might not see it because the view is obstructed ;)(
[Corion]: In Amsterdam, the screen went down to the bottom of the stage (60cm above ground) and the seating was on the ground, meaning that the rows in the back couldn't see the bottom of slides.
[Corion]: There also were some columns that meant that maybe you couldn't see the left/right edge of a slide.
[ambrus]: Corion: Sure. I've had a course in a 50 seat lecture hall that has two fucking columns in the middle.
[Corion]: Talking about it, the top should be fairly visible in the situations I've experienced at least. The top is uncomfortable for people in the first three rows, but that's life ;)

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